at least in the US, income tax brackets are done in a mostly reasonable way. if the tax bracket is at $30,000 and you make $35,000, then you’d pay a low percentage of the first $30k and a higher percentage of the last $5k. so you can’t lose money by earning an extra dollar, at least only considering income tax.

it’s other benefits, tax credits, social programs, etc. that sometimes end up being designed with perverse incentives.